Brain metabolomic profiling reveals ischemia-dominant disruption of metabolic pathways and tissue homeostasis in neonatal hypoxic-ischemic brain injury.

In neonatal hypoxic-ischemic brain injury (HIBI), a common form of perinatal brain damage associated with mortality and neurological disability, the disruption of oxygen and nutrient supply severely impacts brain metabolism. Though therapeutic hypothermia reduces cerebral metabolic rate and improves outcomes, disruption of oxidative metabolism compromising neuronal survival often persists. The complex cerebral metabolic shifts in HIBI remain poorly understood. We directly analyzed the metabolome (LC-MS) of neonatal hypoxia-ischemia (HI)-affected brain tissue to gain further insight into HIBI pathophysiology, isolate the metabolic effects of ischemia and hypoxia, and identify potential therapeutic targets. Postnatal day 10 mice were subjected to five experimental conditions: HI (n = 9) by unilateral carotid artery ligation (UCAL) and hypoxia exposure; contralateral hemispheres; ischemia (UCAL, n = 8); hypoxia (n = 12); and naive (n = 9). Cerebral hemispheres were analyzed 24h post-HI to capture their acute metabolic state. HI resulted in marked alterations in energy production, amino acid and nucleotide metabolism, and pathways governing neuronal homeostasis. Metabolites and pathways linked to NAD⁺ signaling, glutamate regulation, PI3K/AKT signaling, arginine metabolism, neuroinflammation, and vascular regulation were significantly dysregulated. Importantly, these metabolic changes were largely reproduced by ischemia alone, revealing an ischemia-dominant metabolic phenotype. Overall, brain metabolomic profiling identified ischemia as a primary driver of metabolic dysfunction in neonatal HIBI and highlighted specific metabolic pathways involved in bioenergetic deficit, imbalance of neurodegenerative-neuroprotective mechanisms, inflammation, and vascular function, as candidate targets for future therapeutic strategies aimed at limiting secondary brain injury and mitigating neurodevelopmental sequelae.